Data are sparse on the incidence of carpal tunnel syndrome (CTS) in the general population, and estimates from workplace settings vary widely among workers' compensation, OSHA logs of recordable illnesses, and other administrative data sources. The reasons that some people with work-related CTS do not file compensation claims are believed to include factors as varied as access to medical care and information about work-related morbidity, employers' medical management and return-to-work programs, and workers' perceived job security and expected success in filing compensation claims. The proposed pilot study seeks to determine the feasibility of using data from a large health maintenance organization to estimate the incidence of carpal tunnel syndrome from a relatively well-defined sample of the Massachusetts general population and to estimate the proportion of those incident cases that are likely work-related. Using a retrospective, dynamic cohort study design, computerized files, medical records and structured interviews will be used to identify and characterize CTS cases. Information about etiologically relevant occupational exposures will be obtained from the interviews and scored as to probability of work-relatedness. With cases' permission, employers will be contacted for structured interviews to obtain information regarding knowledge and attitudes about occupational ergonomics and upper extremity musculoskeletal disorders, in-house medical management programs, employee health benefits, and possible costs of work-related CTS. In addition, workers' compensation payment for procedures will be abstracted from the medical charts, and records of workers' compensation claims and indemnity payments will be obtained from the state Department of Industrial Accidents. Work-related cases who did and did not file workers' compensation claims will be compared in an attempt to identify both individual and occupational factors that may act as barriers or incentives to claim filing or receiving benefits. Limited data on cost and social and family burden will be compiled for work-related cases with and without compensation.